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A rapidly mutating virus may be partially responsible for the massive bee die-offs known as colony collapse disorder (CCD), which has wiped out a third of commercial bee colonies annually for the past seven years, a group of U.S. and Chinese researchers reports. Most scientists, including the study's authors, believe CCD is triggered when colonies are weakened by a combination of factors, such as viruses, parasites, and perhaps pesticides. The study published yesterday in the journal mBio found in bees a variant of the tobacco ringspot virus, an RNA virus that likely jumped from tobacco plants, to soy plants, to bees. Weak bee colonies began succumbing to massive die-offs in autumn, and the researchers found those bees were heavily infected with tobacco ringspot — which is believed to affect honeybees' nervous systems — and other viruses. Strong colonies that made it through the winter showed no evidence of infection by tobacco ringspot or Israeli acute paralysis virus, a second virus commonly implicated in CCD. The researchers believe the virus jumped from plants to bees through "bee bread," a concoction of pollen, nectar, and saliva they feed their larvae. Bee infection by tobacco ringspot is the first known instance of a virus from pollen jumping to bees, but roughly one in 20 plant viruses is found in pollen, the researchers note, suggesting pollen should be monitored as a source of infections.

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Photographer Robert Wintner documents the exquisite beauty and biodiversity of Cuba’s coral reefs, which are largely intact thanks to stifled coastal development in the communist nation. View the gallery.

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The Warriors of Qiugang, a Yale Environment 360 video, chronicles a Chinese village’s fight against a polluting chemical plant. It was nominated for a 2011 Academy Award for Best Documentary Short.
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